I'm trying to understand how to do integration tests on ASP.NET Core 6 web API controllers. I've tried following all the guides, SO posts and recommendations I could find but for some reason I keep hitting errors that aren't mentioned in the guides.

EventControllerTests.cs

namespace UnitTests.ProjectToBeTested.Controllers
{
    public class EventControllerTests
    {
        [Fact]
        public async Task EventController_Post_RespondsOkIfRequestContainsCorrectFeilds_SuccessAsync()
        {

            // Arrange
            var application = new WebApplicationFactory<Program>();

            var client = application.CreateClient();
            ...

ProjectToBeTested.csproj

...
    <ItemGroup>
        <InternalsVisibleTo Include="IntegrationTests" />
    </ItemGroup>
...

This throws the following when running the test:

Message:  System.InvalidOperationException : No method 'public static IHostBuilder CreateHostBuilder(string[] args)' or 'public static IWebHostBuilder CreateWebHostBuilder(string[] args)' found on 'Program'. Alternatively, WebApplicationFactory`1 can be extended and 'CreateHostBuilder' or 'CreateWebHostBuilder' can be overridden to provide your own instance.

Stack Trace:  WebApplicationFactory1.CreateWebHostBuilder() WebApplicationFactory1.EnsureServer() WebApplicationFactory1.CreateDefaultClient(DelegatingHandler[] handlers) WebApplicationFactory1.CreateDefaultClient(Uri baseAddress, DelegatingHandler[] handlers) WebApplicationFactory1.CreateClient(WebApplicationFactoryClientOptions options) WebApplicationFactory1.CreateClient() EventControllerTests.EventController_Post_RespondsOkIfRequestContainsCorrectFeilds_SuccessAsync() line 17 --- End of stack trace from previous location ---

This SO post shows up as a possible solution but is using pre-6 using a Startup class. What would the .NET 6 solution be?

If I instead follow the "Basic tests with the default WebApplicationFactory"-guide I can't even build the solution because of the test class constructor throwing

Error CS0051 Inconsistent accessibility: parameter type 'WebApplicationFactory' is less accessible than method 'EventControllerTests.EventControllerTests(WebApplicationFactory)' IntegrationTests C:\...\EventControllerTests.cs

CodePudding user response：

I can't reproduce this. I created two new projects from the command line on .NET 6 RC1 with

dotnet new webapi -o webapi1
dotnet new xunit -o test1
dotnet new sln

Web API project

The only change I made to the Web API project was to add this to the project file:

  <ItemGroup>
    <InternalsVisibleTo Include="test1" />
  </ItemGroup>

Program.cs remained unchanged:

using Microsoft.OpenApi.Models;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
builder.Services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new() { Title = "webapi2", Version = "v1" });
});

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "webapi2 v1"));
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

Test project

In the test project I added a reference to webapi1 and the Microsoft.AspNetCore.Mvc.Testing package.

I changed Unit1.cs to

using Microsoft.AspNetCore.Mvc.Testing;
using Xunit;
using webapi2;

namespace test1;

public class UnitTest1
{
    [Fact]
    public void Test1()
    {
        using var app = new WebApplicationFactory<Program>();
        using var client=app.CreateClient();
    }
}

The projects compiled and the test run succesfully.

CodePudding user response：

Solution:

This was due to the Microsoft.AspNetCore.Mvc.Testing package for the test project using the wrong version (it was using version 5.*). Make sure that you use a version suitable for .NET 6. As of now there is a 6.0.0-rc.2.21480.10 version that works for me.